It is well known to use radio-signalling devices in the case of isolated persons, when for example they find themselves in difficulty during trekking, cross-country skiing, or mountain climbing. However, in the case of a person becoming abducted for ransom or other purpose, such devices have been inefficient since the abductor could readily remove same, and therefore the signalling device would no more indicate the position of the victim. The occurrence of abduction increases nowadays, and such a situation should not be tolerated.